Since oil and gas is almost always found in sedimentary rocks deposited in layers, the trick is to keep the well in one or more of these preferred layers. These layers of rock can vary considerably in thickness, structure, and many other properties. This is why geological knowledge and experience is so important. However, the geologist can not work alone. Engineers and others are a vital part of the process and we must all work together.
I am an independent, consulting geologist, trained and experienced in exploration and interpretation, so my input here will be from that perspective. However, I will be posting what I consider relevant articles from geologists, engineers, geophysicists and others. I hope to generate input and discussion from those interested in this relatively new technology. Drilling, interpreting and completing these horizontal wells is expensive and challenging. It requires the coordinated effort of a team of experts.
Please add your comments, experience, and questions. If I don't have the answers, I'm sure I can find someone who does. Sharing our knowledge is the name of the game.